The present invention relates generally to torque oscillation compensation for electric vehicle motors, and more particularly, to a torque oscillation compensation system and circuit that uses velocity feedback derived from an electric vehicle motor to compensate for torque pulsations experienced at the output shaft of an electric motor.
Electric drive train systems can exhibit torque pulsations. These torque pulsations can cause motor bearing and tire wear. The torque pulsations can also cause undesirable drive wain/vehicle vibration. Prior art devices for use in stabilizing electric vehicles have attempted to implement vehicle stabilization using gyroscopic compensation. However, gyroscopic techniques have not yet proved to be feasible for use on electric vehicles.
It has been known for some time that induction motors that are driven by variable frequency controllers exhibit torque fluctuations, especially at low speed. Electric vehicles that are propelled by such induction motors therefore exhibit torque fluctuations. This results in unstable operation at low speed and can affect the marketability of the vehicle. Consequently, the prior art approaches are not cost effective and/or technically suited for use in many electric drive train applications.
Accordingly, it is an objective of the present invention to provide for a torque oscillation compensation circuit that uses velocity or speed feedback derived from an electric vehicle motor to generate a compensation signal that compensates for pulsations experienced at the output shaft of an electric motor.